Sendmail

Sendmail is the classical SMTP server from the unix world. It was originally coded long time ago, when the internet was a safer place, and back then, security didn't matter as much as does today. Therefore it used to have several security bugs and it got some bad reputation for that. But those bugs are long fixed and a recent sendmail version is as safe as other SMTP servers. If your top priority is security, you should probably use netqmail, however.

The goal of this article is to setup Sendmail for local users accounts, without using mysql or other database, and allowing also the creation of mail-only accounts. This article only explains the required steps configuring Sendmail; after that, you probably want to add IMAP and POP3 access, so you should install Dovecot.

local-host-names

Create the file /etc/mail/local-host-names and put there your domains:

localhost
your-domain.com
mail.your-domain.com
localhost.localdomain

access.db

Create the file /etc/mail/access and put there the base addresses where you want to be able to relay mail. Lets supose you have a vpn on 10.5.0.0/24, and you want to relay mails from any ip in that range:

10.5.0 RELAY
127.0.0 RELAY

Then process it with

makemap hash /etc/mail/access.db < /etc/mail/access

aliases.db

Edit the file /etc/mail/aliases and uncomment the line #root: human being here and change it to be like this:

root: your-username

You can add aliases for your usernames there, like:

coolguy: your-username
somedude: your-username

Then process it with

newaliases

virtusertable.db

Create the file /etc/mail/virtusertable and put there aliases that includes domains (useful if your server is hosting several domains)